navel piercing; belly button ring
Refers to both the piercing itself and the jewelry worn in it. The abbreviation へそピ is also used colloquially.
See also: へそピ
I got my navel pierced for the summer.
She's wearing a sparkly belly button ring.
Compound of 臍 (へそ, 'navel') and ピアス (from English 'pierce' or 'piercing'). A straightforward modern loanword-based coinage.